Our Lennox Pulse G14 is short cycling up to 5 times before running a normal length heating cycle. It turn on and off about every 10-20 seconds. Lennox certified repairmen are coming out to service it again. Hoped someone might have ideas what parts should be looked at for this issue. Repairmen replaced a small flapper gasket like thing 2 weeks ago and it made no difference. Help!

not yet, no. They came yesterday no charge and adjusted something on the thermostat. They also checked out the connections again in the furnace. The coming on/off is less often but still doing it. i think it is a short or bad wire in the thermostat... is that possible? the thing is 20 years old now. The furnace has otherwise completely checked out and is in running order.